Light-Emitting Diode Device

ABSTRACT

A light-emitting diode device is disclosed. The light-emitting diode device includes a transparent substrate with a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface; a first light-emitting structure; a second light-emitting structure; a connecting layer, connected to the first light-emitting structure and the second light-emitting structure; a circuit arranged between the transparent substrate and the first light-emitting structure, and having a portion formed on the first surface without extending to the second surface; and a structure with diffusers, covering the first light-emitting structure and the second light-emitting structure on the first surface without crossing over the side surface.

REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patent application Ser. No. 13/282,317, filed on Oct. 26, 2011, which claims the right of priority based on TW application Ser. No. 096143129, filed Nov. 13, 2007, entitled “LIGHT-EMITTING DEVICE PACKAGE”, U.S. application Ser. No. 12/292,161, filed Nov. 13, 2008, entitled “LIGHT-EMITTING DEVICE PACKAGE”, and the contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

A light-emitting diode device is disclosed.

2. Description of the Related Art

Generally, light-emitting diodes (LEDs) having transparent substrates are divided into face-up type and flip-chip type. For the face-up type, the light-emitting diodes are attached to carriers by gels or metals; for flip-chip type, the light-emitting diodes are attached to carriers by metals or solders with the attached surface as the light extraction surface of the light-emitting diode or the surface parallel to it. Because the light extracted from the light-emitting layer of the light-emitting diodes are 360 degree, the light emitting downward is generally reflected to the front of the light extraction side by the reflecting layers or extracted from the transparent substrates. The thickness of the transparent substrate should be properly adjusted so that the brightness of the light extraction is acceptable. Besides, when the size of the light-emitting diodes is larger, there are more reflected light passing through the multi-quantum well (MQW) in the light-emitting layer. The light efficiency is reduced because of light absorption.

FIG. 1 shows a schematic illustration of conventional light-emitting diode device. As shown in FIG. 1, a light-emitting diode chip 100 is attached to a carrier 3 with an attached surface 1 which is parallel to the front light extraction surface 4 of the light-emitting diode chip 100. The light emitted downward is reflected to the front light extraction surface 4 or the lateral light extraction surface 5 by the reflector 2. The disadvantage of this device is when the size of the light-emitting diode chip is larger, there are more reflected light passing through the multi-quantum well (MQW) in the light-emitting layer. The light efficiency is reduced because of light absorption.

SUMMARY

A light-emitting diode device is disclosed. The light-emitting diode device includes a transparent substrate with a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface; a first light-emitting structure; a second light-emitting structure; a connecting layer, connected to the first light-emitting structure and the second light-emitting structure; a circuit arranged between the transparent substrate and the first light-emitting structure, and having a portion formed on the first surface without extending to the second surface; and a structure with diffusers, covering the first light-emitting structure and the second light-emitting structure on the first surface without crossing over the side surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide easy understanding of the invention, and are incorporated herein and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to illustrate the principles of the invention.

FIG. 1 is an illustration of conventional light-emitting diode device.

FIG. 2 is a lateral view of the light-emitting structure of the present invention.

FIG. 3 is a lateral view of the light-emitting structure of another embodiment of the present invention.

FIG. 4 is a lateral view of the light-emitting device of the present invention.

FIG. 5 is a lateral view of the light-emitting device of another embodiment of the present invention.

FIG. 6 is a lateral view of the light-emitting diode device of the present invention.

FIG. 7 is a lateral view of the light-emitting diode device of another embodiment of the present invention.

FIG. 8 is a lateral view of the light-emitting diode device of another embodiment of the present invention.

FIG. 9 is a lateral view of the light-emitting diode device of another embodiment of the present invention.

FIG. 10 is an illustration of the backlight module of the liquid crystal display device of the present invention.

FIG. 11 is an illustration of another backlight module of the liquid crystal display device of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

FIGS. 2 and 3 show the light-emitting structures in accordance with one embodiment of the present application. Referring to FIG. 2, a structure of a light-emitting diode chip 200 includes an epitaxial structure 202 formed on the growth substrate 201 by metal-organic chemical vapor deposition (MOCVD) process or an epitaxial structure formed on the supporting substrate by a bonding process, wherein the epitaxial structure having a first conductivity type semiconductor layer 202 a, an active layer 202 b, and a second conductivity type semiconductor layer 202 c. A first electrode 203 and a second electrode 204 are disposed on the epitaxial structure 202 to form a horizontal structure of the light-emitting diode chip 200.

The material of the growth substrate can be transparent material such as Sapphire, ZnO, or AlN. The growth substrate can also be high thermal-dissipative materials such as diamond like carbon (DLC), graphite, Si, SiC, GaP, GaAs, or LiAlO₂.

Referring to FIG. 3, a structure of a light-emitting diode chip 300 includes an epitaxial structure 302 formed on the growth substrate 301 by metal-organic chemical vapor deposition (MOCVD) process or an epitaxial structure formed on the supporting substrate by a bonding process, wherein the epitaxial structure having a first conductivity type semiconductor layer 302 a, an active layer 302 b, and a second conductivity type semiconductor layer 302 c. A first electrode 303 is formed on the first side of the epitaxial structure 302 and the second electrode 304 is formed on the second side opposite to first side of the epitaxial structure 302 to form a vertical structure of the light-emitting diode chip 300.

The material of the support substrate can be transparent material or electrically insulating material such as sapphire, diamond, glass, epoxy, quartz, acrylate, ZnO, or AlN. The support substrate can also be high thermal-dissipative materials or reflective materials such as Cu, Al, Mo, Cu—Sn, Cu—Zn, Cu—Cd, Ni—Sn, Ni—Co, Au alloy, diamond like carbon (DLC), graphite, carbon fiber, metal matrix composite (MMC), ceramic matrix composite (CMC), polymer matrix composite (PMC), Si, IP, ZnSe, GaAs, SiC, GaP, GaAsP, ZnSe, InP, LiGaO₂, or LiAlO₂.

FIG. 4 is an illustration of the light-emitting device 400 in accordance with one embodiment of the present application. A structure of the light-emitting diode chip such as the light-emitting diode chip 200 or 300 is attached to a first surface 404 a of the transparent substrate 404 to form a light-emitting device 400. The structure of the light-emitting diode chip 200 includes a growth substrate 201, an epitaxial structure 202 formed on the growth substrate 201 wherein the epitaxial structure having a first conductivity type semiconductor layer 202 a, an active layer 202 b, and a second conductivity type semiconductor layer 202 c; a first electrode 203 and a second electrode 204 formed on the epitaxial structure 202.

The material of the transparent substrate can be sapphire, diamond, glass, epoxy, quartz, acrylate, ZnO, AlN, or SiC.

FIG. 5 is an illustration of the light-emitting device 500 in accordance with one embodiment of the present application. A structure of the light-emitting diode chip such as light-emitting diode chip 200 or 300 is attached to a transparent substrate 504 containing phosphor materials to form a light-emitting device 500. The structure of the light-emitting diode chip 200, includes a growth substrate 201, an epitaxial structure 202 formed on the growth substrate 201 wherein the epitaxial structure having a first conductivity type semiconductor layer 202 a, an active layer 202 b, and a second conductivity type semiconductor layer 202 c; a first electrode 203 and a second electrode 204 formed on the epitaxial structure 202. Following, a phosphor layer 505 is positioned over and around the structure of the light-emitting diode chip 200 to form a light-emitting device 500.

As shown in FIG. 4 and FIG. 5, the structure of the light-emitting diode chip 200 or 300 can be attached to the transparent substrate 404 or 504 by a connecting layer (not shown in FIG. 4 and FIG. 5). The material of the connecting layer can be an insulating material such as polyimide, BCB, PFCB, MgO, SUB, epoxy, acrylic resin, COC, PMMA, PET, PC, polyetherimide, fluorocarbon polymer, silicone, glass, Al₂O₃, SiO_(x), TiO₂, SiN_(x), SOG, or other organic adhesive material. The material of the connecting layer can also be a conductive material such as ITO, InO, SnO, CTO, ATO, AZO, ZTO, IZO, Ta₂O₅, DLC, Cu, Al, Sn, Au, Ag, Ti, Ni, Pb, Cr, Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, or Au alloy, and so on. The material of the connecting layer can also be a semiconductor layer such as ZnO, AlGaAs, GaN, GaP, GaAs, GaAsP, and so on.

FIG. 6 is a lateral view of the light-emitting diode device 10 in accordance with one embodiment of the present application. The aforementioned structures of light-emitting device 400 or 500 are applicable to the light-emitting diode device 10 shown in the embodiments of the present application, and the light-emitting device 400 is chosen to describe the embodiments to avoid repeating description. Referring to FIG. 6, a carrier 601 having a reflective inside wall 602 is provided wherein the carrier can be a printed circuit board, a ceramics substrate, or a silicon substrate. A transparent substrate 404 of the light-emitting device 400 is attached to a platform 603 of the carrier 601 by an adhering material, wherein the first surface 404 a of the transparent substrate 404 and its parallel surface (the second surface 404 b) are disposed on the platform 603. In a preferred embodiment, the transparent substrate 404 is approximately perpendicular to the platform 603. In addition, the p and n electrode of the light-emitting device is electrically connected to a p electrode 606 and an n electrode 607 of the carrier respectively to form a light-emitting diode device 10. The light emitted from the active layer of the light-emitting device 400 is omnidirectional. The light emitted to the first surface 404 a of the transparent substrate 404 is passed through the transparent substrate 404, and emitted from the second surface 404 b of the transparent substrate 404. The light is reflected from the reflective inside wall 602 of the carrier and leaves the light-emitting diode device 10. Besides, a lens 604 can be positioned over the light-emitting diode device 10 to increase the light efficiency.

FIG. 7 is a lateral view of the light-emitting diode device 20 of the second embodiment of the present invention. A transparent substrate 404 of a light-emitting device 400 is attached to a carrier 701 having a reflector 703 by an adhering material 704 wherein the carrier is a printed circuit board, a ceramics substrate, or a silicon substrate. In a preferred embodiment, the transparent substrate 404 is approximately perpendicular to the carrier 701. The p and n electrode of the light-emitting device 400 is electrically connected to the p and n electrode of the carrier respectively. The diffusers 702 are filled in the light-emitting diode device 20 to scatter the light emitted from the light-emitting device 400. The light (as the arrows indicating in FIG. 7) passes through the transparent substrate 404 and is emitted out from the second surface 404 b to form a lateral light-emitting diode device 20.

FIG. 8 is a lateral view of the light-emitting diode device 30 of another embodiment of the present application. A multi-LED structure 800 is formed by bonding two horizontal structures of the light-emitting diode chips 200 and 200′ back to back through a connecting layer (not shown in the figure). The structure of the light-emitting diode chip 200 can comprise GaN series material which emits blue light and the structure of the light-emitting diode chip 200′ can comprise AlGaInP series material which emits red light. Besides, an intermediate substrate 801 can be formed between the structures of the light-emitting diode chips 200 and 200′. The intermediate substrate 801 can be a transparent growth substrate of the blue light-emitting diode chip 200. Besides, a mirror (not shown in the figure) can be further formed at one side of the intermediate substrate 801 to enhance the light extraction efficiency of the light-emitting diode device 30.

The material of the connecting layer can be insulating material such as polyimide, BCB, PFCB, MgO, SUB, epoxy, Acrylic Resin, COC, PMMA, PET, PC, polyetherimide, fluorocarbon polymer, silicone, glass, Al₂O₃, SiO_(x), TiO₂, SiN_(x), SOG, or other organic adhesive material. The material of the connecting layer can also be a conductive material such as ITO, InO, SnO, CTO, ATO, AZO, ZTO, IZO, Ta₂O₅, DLC, Cu, Al, Sn, Au, Ag, Ti, Ni, Pb, Cr, Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, or Au alloy, and so on. The material of the connecting layer can also be a semiconductor layer such as ZnO, AlGaAs, GaN, GaP, GaAs, GaAsP, and so on.

The multi-LED structure 800 is attached to the transparent substrate 404 and electrically connected to the circuit (not shown in the figure) on the transparent substrate 404 through directly bonding, solder bonding, and/or wire bonding. The transparent substrate 404 of the light-emitting device 800 is further attached to a carrier 701 having a reflective surface 703 by an adhering material 704 wherein the carrier 701 is a printed circuit board, a ceramics substrate, or a silicon substrate. In a preferred embodiment, the transparent substrate 404 is approximately perpendicular to the carrier 701. The circuit (not shown in the figure) of the transparent substrate 404 is electrically connected to a first electrode (ex. p electrode) 701 a and a second electrode (ex. n electrode) 701 b of the carrier 701 respectively. Diffusers 702 are filled in the light-emitting diode device 30 to scatter the light emitted from the light-emitting device 800. The light (as the arrows indicating in FIG. 8) passes through the transparent substrate 404 and is emitted out from the second surface 404 b. In this embodiment, the structure of the light-emitting diode chip 200 and the structure of the light-emitting diode chip 200′ are electrically connected to each other in parallel.

FIG. 9 is a lateral view of the light-emitting diode device 40 of one embodiment of the present application. A multi-LED structure 900 is formed by bonding one horizontal structure of the light-emitting diode chip 200 and one vertical structure of the light-emitting diode chip 300 back to back through a conductive bonding layer 901. The structure of the light-emitting diode chip 200 can comprise GaN series material which emits blue light and the structure of the light-emitting diode chip 300 can comprise AlGaInP series material which emits red light. Besides, an intermediate substrate (not shown in the figure) can be formed between the structures of the light-emitting diode chips 200 and 300. The intermediate substrate can be a transparent growth substrate of the blue light-emitting diode chip 200. Besides, a mirror (not shown in the figure) can be further formed at one side of the intermediate substrate to enhance the light extraction efficiency of the light-emitting diode device 40.

The multi-LED structure 900 is attached to the transparent substrate 404 and electrically connected to the circuit (not shown in the figure) on the transparent substrate 404 through directly bonding, solder bonding, and/or wire bonding. The transparent substrate 404 of a light-emitting device 900 is further attached to a carrier 701 having a reflective surface 703 by an adhering material 704 wherein the carrier 701 is a printed circuit board, a ceramics substrate, or a silicon substrate. In a preferred embodiment, the transparent substrate 404 is approximately perpendicular to the carrier 701. The circuit (not shown in the figure) of the transparent substrate 404 is electrically connected to a first electrode (ex. p electrode) 701 a and a second electrode (ex. n electrode) 701 b of the carrier 701 respectively. The diffusers 702 are filled in the light-emitting diode device 40 to scatter the light emitted from the light-emitting device 900. The light (as the arrows indicating in FIG. 9) passes through the transparent substrate 404 and is emitted out from the second surface 404 b. In this embodiment, because the vertical structure of the light-emitting diode chip 300 is electrically connecting to the horizontal structure of light-emitting diode chip 200 through the conductive bonding layer 901, the structure of the light-emitting diode chip 200 and the structure of the light-emitting diode chip 300 are electrically connected to each other in series.

FIG. 10 is a lateral-view of a backlight module 50 of the liquid crystal display devices accompanied with any one of the embodiments of the present application. A plurality of light-emitting diode devices 10 is attached to a carrier 801 having a reflecting layer 802 on the bottom by an adhering material 804 wherein the carrier is a printed circuit board, a ceramics substrate, or a silicon substrate. The p and n electrode of the light-emitting device is electrically connected to the p and n electrode of the carrier respectively wherein the structure of the light-emitting diode device and the manufacturing method thereof is the same with illustration of FIG. 6 described above. The light emitted from the plurality light-emitting diode devices passes through the thin-film material 803 with different functions, such as prism sheet, to uniformly emit the desired light, and a backlight module 30 of the liquid crystal display device is formed accordingly.

FIG. 11 is an illustration of another backlight module 60 coupled with a polarizer of the liquid crystal display device as shown in FIG. 10. A polarizer 902 having a reflecting layer 901 on the bottom is covered with a thin-film material 903 on the top layer. The polarizer coupled with a plurality of lateral light-emitting diode device 20 to form a backlight module 60 of the liquid crystal display device. The lateral light emitted from the backlight module 60 is guided to the polarizer 902 (as the arrows indicating in FIG. 11) wherein the downward light is reflected from the reflecting layer 901 to the polarizer 902. The mixed and polarized light is emitted through the thin-film material 903 to the other structure of the liquid crystal display device, such as liquid crystal layer wherein the emitting direction of the light is as the arrows indicating in FIG. 11. 

What is claimed is:
 1. A light-emitting device, comprising: a transparent substrate having a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface; a first light-emitting structure; a second light-emitting structure; a connecting layer, connected to the first light-emitting structure and the second light-emitting structure, and disconnected from the transparent substrate; a circuit arranged between the transparent substrate and the first light-emitting structure, and having a portion formed on the first surface without extending to the second surface; and a structure with diffusers, covering the first light-emitting structure and the second light-emitting structure on the first surface without crossing over the side surface.
 2. The light-emitting device of claim 1, further comprising an intermediate substrate arranged between the first light-emitting structure and the second light-emitting structure.
 3. The light-emitting device of claim 1, further comprising a carrier connected to the side surface and separated from the second surface.
 4. The light-emitting device of claim 3, wherein the transparent substrate is arranged against the carrier by an angle of 45-135 degrees.
 5. The light-emitting device of claim 3, further comprising a reflector arranged on the carrier.
 6. The light-emitting device of claim 3, wherein the carrier is a printed circuit board, a ceramics substrate, or a silicon substrate.
 7. The light-emitting device of claim 3, wherein the carrier comprises a top surface which is covered by the structure with diffusers.
 8. The light-emitting device of claim 1, wherein the first light-emitting structure comprises a first upper surface, a first lower surface opposite to the first upper surface and facing the connecting layer, and a first bonding pad formed on the first upper surface.
 9. The light-emitting device of claim 8, further comprising a reflective layer arranged on the first lower surface.
 10. The light-emitting device of claim 1, wherein the first light-emitting structure and the second light-emitting structure are configured to emit different color lights.
 11. The light-emitting device of claim 1, wherein the first light-emitting structure and the second light-emitting structure are configured to emit a blue light and a red light.
 12. The light-emitting device of claim 1, wherein the first light-emitting structure and the second light-emitting structure are electrically connected to each other in series.
 13. The light-emitting device of claim 1, wherein the first light-emitting structure and the second light-emitting structure are electrically connected to each other in parallel.
 14. The light-emitting device of claim 1, wherein the connecting layer is made of insulating material or conductive material.
 15. The light-emitting device of claim 1, wherein the transparent substrate comprises a phosphor material. 